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12-year-old healthy female athlete presents with mole on heel
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A 12-year-old healthy female athlete presented to the dermatology clinic for a mole check. The patient was most concerned about a new black spot on her left heel. She noticed it 2 weeks earlier. It did not resolve with rubbing alcohol. It was asymptomatic and had not changed in size or color since she noticed it. There was no pain, and she continued to attend field hockey practice multiple times per week without any issues.
She had a history of multiple blistering sunburns and did not like to wear sunscreen. She had a prior scalp nevus that had been excised and shown to be benign without atypia. There was a family history of melanoma in her paternal grandmother at the age of 85 years. On exam, there was a 5-mm brown-red macule on the left heel (Figure 1). The patient had multiple well-demarcated, evenly pigmented brown macules and papules scattered on the torso, scalp and extremities.
Can you spot the rash?
A. Acral nevus
B. Tinea nigra
C. Melanoma
D. Wart
E. Talon noir
Talon noir (choice E), also known as black heel or calcaneal petechiae, is a common condition that may be confused with more concerning diagnoses. It is sometimes referred to as “tache noir” when it occurs on the hands or other sites besides the feet. The condition usually occurs in athletes who participate in sports that involve sudden stops, such as tennis or basketball. These stops create shearing forces in the skin that cause bleeding from the superficial dermal blood vessels. This blood is visible in the most superficial layer of the skin. Colors can range from black to purple to gray. They often appear as multiple punctate macules but can coalesce into what appears to be a more solid area.
Sometimes the diagnosis may be in question when there is not a specific history of trauma or the patient does not participate in sports. Paring the area with a No. 15 blade can remove some of the thick stratum corneum where the blood is trapped, helping to confirm the diagnosis. Biopsy is rarely necessary to differentiate talon noir from other etiologies.
Black spots on the heel have a relatively limited differential diagnosis. Melanocytic neoplasms, warts and tinea nigra may be considered. Children can develop new nevi throughout childhood into early adulthood, and so the new appearance of a pigmented lesion on the plantar surface is not always cause for concern as in adults. Acral melanoma is exceedingly rare in children. Pigmented lesions on acral surfaces that do not resolve with paring should be evaluated by a dermatologist if there is concern regarding their appearance.
Tinea nigra is a rare fungal infection that occurs on acral surfaces. It is caused by Hortaea werneckii, a dermatophyte that grows in soil and sewage under humid conditions. There is typically minimal, if any, inflammation. Mild scale can be present. Lesions are usually light brown and continue to grow over weeks. A potassium hydroxide prep will demonstrate fungal hyphae.
Warts can cause black dots on the plantar surface. They are caused by HPV, and thrombosed capillaries result in black dots that may be mistaken for talon noir. Paring that resulted in pinpoint bleeding would be more consistent with a wart. Warts also obliterate normal skin lines, whereas talon noir often occurs over a callused area where skin lines are accentuated.
In summary, consider talon noir for any new brownish-red or black lesion on the foot, particularly the heel, that occurs suddenly in an athlete. Providers can reassure patients that talon noir resolves on its own within several weeks and is more common in athletes who make sudden stops and starts.
- References:
- Bolognia JL, et al. Dermatology. 4th ed. New York, NY: Elsevier; 2018.
- Googe AB, et al. Postgrad Med J. 2014;doi:10.1136/postgradmedj-2014-132996.
- Paller AS, et al. Hurwitz Clinical Pediatric Dermatology: A Textbook of Skin Disorders of Childhood and Adolescence. 5th ed. London: Elsevier; 2016.
- For more information:
- Colleen H. Cotton, MD, is a pediatric dermatology fellow at The Children’s Hospital of Philadelphia. She can be reached at cottonch@email.chop.edu.
- Marissa J. Perman, MD, is an attending physician at The Children’s Hospital of Philadelphia.
Disclosures: Cotton and Perman report no relevant financial disclosures.